Advances in processing copper-nickel-tin alloys have led to interest in these alloys for applications where electrical conductivity, corrosion resistance, mechanical strength and mechanical ductility are of concern. In the field of communications, for example, such applications include the manufacture of electrical wire, springs, and relay elements, applications in which copper-nickel-tin alloys can beneficially replace the traditionally used copper-beryllium and phosphor-bronze alloys. Copper-nickel-tin alloys are also potentially applicable in shipbuilding and in sea water desalination plants.
Achievement of high levels of strength and ductility in copper-nickel-tin alloys is largely dependent on cold working and heat treating homogenized alloys. Such processing is a subject of "Spinodal Cu-Ni-Sn Alloys Are Strong and Superductile" by John T. Plewes published in Metal Progress, July 1974, pages 46-48, where amounts of cold work in combination with aging times and temperatures are disclosed which lead to high degrees of strength and ductility in the processed alloy.
The preparation of a homogenized Cu-Ni-Sn ingot can be accomplished by normal practice such as hot working provided the thickness of the ingot as cast does not significantly exceed one inch and provided further that neither its tin nor its nickel contents significantly exceed 4.5 percent. Attempts at applying hot working to thicker ingots or ingots richer in tin or nickel lead to undesirable effects such as surface cracking, edge cracking, and alligatoring. The latter, described in general terms in "Deformation Processing" by Walter A. Backofen, Adison Wesley, 1972, consists in deep horizontal splitting of the end of the slab upon delivery from the rolling mill.